Russ Collins RC 388 camshaft Identification

Anybody ever used or heard of these camshafts? Any specs appreciated. They are on a Z1 and both intake and exhaust are stamped the same. Even has the RC sprockets.

I can’t help but I took a chance on very similar set. Bought specifications unknown. Maybe together we can find out

This was included in the auction.

Cool! I want them! And Remember those drilled and machined with no oil groove R.C. Eng. lifter buckets they made?? Talk about Rare! Nice score if you just bought that engine!
No info? Should be a drop in hot street cam?

Marty in Buffalo

Sounds Good Mikaw! I haven't measured these yet but they don't resemble a drop-in set, way too much lift i think? Are these what Youre talking about Marty?

I know.. insert insert.

Now I see the 6a and 6r on the sprocket. It’s got to be 6 degrees advance and retard. It’s bolted in the E. The one I just bought must be smaller lift being labeled “370” vs your “388”. I don’t have mine yet. I’ll mic and post when they arrive. I just hope they are 1.10 base circle.

I was reading through a Denco catalog and saw the lightened lifter cups. I didn’t know they were minus the oil grove to help eliminating shim cant and possible spitting.

The lightened buckets i will Not reuse. A couple have seemed to warp and are not a smooth fitment. And as You mentioned, no oil groove for suction. I'll go with a set of "cheap" shim unders from a KZ650. Plentiful and purposeful. I don't know about the location of sprocket bolts, just how it came out of the engine? They are in a different location on the other cam.

My cams arrived today. I’m a real rookie with cam numbers. To me these look just slightly bigger then stock at .350 lift. Do the numbers on the included sheet give the experts any more details. Are they any big deal. I just picked up a 70mm set of wiseco 10.5 compression pistons I was planning to install on my 78 kz1000 just to freshen up the engine. Are theses cams worth the effort to install.

Asphalt900 not sure if anything on the included photo helps beyond telling you they are R.C. Engineering brand.

Looking at specs from other manufacturers, I'm surprised by how long the duration number is for those cams. If they are actually 306, that's a huge number compared to other similar cams.

Here are numbers from some similar period cams.

RC CAM #RC370
Lift Duration Timing LS
in .350 306 deg. 43/83 110
ex .350 306 deg. 83/43 110

Andrews 2x:
Lift Duration Timing LS
in .360 258 deg. 23/55 106
ex .360 258 deg. 55/23 106

Web 118 grind
Lift Duration Timing LS
in. .365 286 deg. 17.5/47.5 105
ex. .365 286 deg. 47.5/17.5 105

Yoshimura Road Special
Lift Duration Timing LS
in. .354 260 deg. 25/55 105
ex. .338 260 deg. 55/25 105

Here is the overlap for each cam (assuming I did the math right). You can see how much larger the RC is than the others.

#RC370 : 86 deg.
Andrews 2x : 46 deg.
Web 118 : 35 deg.
Yosh RS : 50 deg.

Looking over the web cams, the biggest cam they make has a duration of 300 degrees, but still has only 50 degrees of overlap, and that's a huge 0.500 Pro-Stock cam.

I don't know enough about cam tuning to know how a moderate lift but very long duration and overlap camshaft will perform.

But that is what you'll need to look into, because the duration of these RC cams are well outside the norm. It seems like these were likely made with a very specific goal in mind. It's too bad the spec sheet doesn't say what that was.

www.webcamshafts.com/pages_vehicles/moto...e/kawasaki/1730.html

So I can't say that I have any experience picking a cam for a 4 cylinder bike, yet, but when I was choosing a cam for another race bike, I gathered that long duration cams tended to need higher RPMs to be happy while high lift, shorter duration cams were better at building torque.

Those Webcam specs are measured at .050" valve lift. Most likely the Russ Collins cams are not.
To add a data point the cams in the KZ750 were 270 degrees duration so 300 isn't crazy long in comparison for an aftermarket cam.